Search PubMed⌕ Search

Biomedical subjects

R S Lord

Publications and source records attributed to R S Lord.

At least 145 records · Page 8Linked to original sources
PubMed1971

Pressure waves and gradients in the canine thoracic duct.

1. Pressures have been measured in the thoracic duct of anaesthetized and conscious dogs to ascertain the mean pressures, the nature of the pressure waves and the pressure gradients along the duct and between it and the great veins.2. The average mean pressure in the thoracic duct of ten anaesthetized dogs was 1.4 mm Hg. The pressure waves were secondary to respiration and the pulsations of the aorta. No waves were transmitted from the great veins.3. Pressures in conscious dogs varied from day to day, sometimes being positive, sometimes negative. They were increased by panting and by drinking.4. The pressure gradients along the duct were small, no more than 0.5-2.0 mm Hg along its whole length.5. No evidence was found of spontaneous contractions of the duct.

Anesthesia↗
PubMedDate not supplied

Surgical treatment of acute deep venous thrombosis.

In patients with venous thrombotic disease and in whom anticoagulation or thrombolytic therapy is inappropriate, ineffective, or even contraindicated, insertion of vena caval filters or venous thrombectomy must be considered. The primary indication for the placement of vena caval filters is in patients who have developed a pulmonary embolus and in whom anticoagulation is either contraindicated or in whom anticoagulation must be discontinued because of the development of bleeding complications. At the present time, either the Greenfield filter placed through a jugular, femoral, or axillary venotomy or the bird's nest filter are appropriate and appear to be the most effective and least fraught with complications. The use of venous thrombectomy has waxed and waned over the last several decades. At the present time, the procedure is advocated mainly for lower limb venous thrombosis which is extensive enough to threaten limb viability. On occasion, it may be appropriate to extend the indications for venous thrombectomy to include femoral thrombosis of less than 10 days duration or iliac thrombosis of less than 3 weeks duration with floating thrombi at the level. Technical modifications which improve the patency of the obliterated veins which are predisposed to rethrombosis include the creation of a temporary arteriovenous fistula and meticulous care in removing the entire clot. The patient should be treated with anticoagulants postoperatively to prevent a recurrence of the problem. The main theoretical advantage of venous thrombectomy is a reduced incidence of postthrombotic syndrome. Objective data to support this contention do not exist.

Hemodynamics↗
PubMedDate not supplied

Ultrastructural and immunohistochemical analysis of early myocardial changes following transmyocardial laser revascularization.

BACKGROUND AND AIM OF THE STUDY: Transmyocardial laser revascularization (TMR) has demonstrated significant relief in patients presenting with refractory angina. However, the mechanism by which TMR improves clinical symptoms is unclear. This study analyzes the early immunohistochemical and ultrastructural features of the human myocardium following TMR. METHODS: Specimens of myocardium that contained laser channels were removed in toto at autopsy from three male patients, ages 41, 57, and 65 (mean age 55.8) who had died 1 to 11 days (mean 6.8) following laser revascularization. Consecutive parallel sections of specimens were stained with cell-type specific antibodies to CD3 (to identify T-lymphocytes), CD68 (macrophages), Factor VIII (endothelial cells), and myosin (myocytes). Additionally, adjacent areas of myocardium that contained laser channels were processed and analyzed by transmission electron microscopy. RESULTS: The internal lining surface of laser channels was composed of vacuolized and condensed myocardial debris. No obvious connections were noted between laser channels and the ventricular cavity. No endothelialization of channels was observed, whereas the adjacent noninjured myocardium demonstrated microvessels lined by well-preserved endothelial cells. The laser channels were surrounded by zones of necrotic cardiomyocytes. CONCLUSIONS: Our observations suggest that laser channels are not lined by endothelial cells during the early stages following TMR. Mechanisms other than direct myocardial perfusion from the ventricular cavity by patent endothelialized channels may explain the immediate relief from angina provided by TMR.

Adult↗